I just did this about a week ago when I replaced my tubes (80k miles wore through the titanium nitriding). If you've ever replace fork bushings before, it's pretty much the same thing. The issue is you need something long enough. I turned a piece on my lathe and screwed it onto a piece of 3/4" black pipe. Whatever you use can't have too rounded an edge or it'll have difficulty getting purchase on the thin bushing.